Vector correlations in the 355 nm photolysis of thermal NO₂

Correlations between the NO₂ transition moment μ, the fragment velocities v and the NO rotational angular momentum J have been made for four NO(v = 0, J) states which span the most populated rotational levels formed by photolysis at 355 nm of a sample of NO₂ at 298 K. Correlations involving μ are seen to be decreased in comparison with those at lower temperatures, and in particular the translational anisotropy factor β is reduced by a factor of ca. 2. A speed independent value of β = 0.7 is shown to describe the fast O(³P) atoms formed under these conditions and can be used in the analysis of the Doppler profiles measured in studies of their reactions with H₂S by means of the 'photoloc' technique. Measured rotational distributions in v = 0 show some deviations from phase space theory, particularly at high J.